K8S 模拟项目 pod 发布
目录
项目生命周期:
创建 ---》发布 ---》更新 ---》回滚 ---》删除
Pod 类型：
- port：port 是 k8s 集群内部访问 service 的端口，即通过
clusterIP:port可以访问到某个 service。- nodePort：nodePort 是外部访问 k8s 集群中 service 的端口，通过
nodeIP:nodePort可以从外部访问到某个 service。- targetPort：targetPort 是 pod 的端口，从 port 和 nodePort 来的流量经过 kube-proxy 流入到后端 pod 的 targetPort 上，最后进入容器。
- containerPort：containerPort 是 pod 内部容器的端口，targetPort 映射到 containerPort。
K8S 集群提供外部服务图：
1. 创建启动 nginx 实例（kubectl run）
[root@master ~]#kubectl run nginx --image=nginx:1.14 --port=80 --replicas=3
kubectl run --generator=deployment/apps.v1 is DEPRECATED and will be removed in a future version. Use kubectl run --generator=run-pod/v1 or kubectl create instead.
deployment.apps/nginx created
[root@master ~]#kubectl get pods
NAME READY STATUS RESTARTS AGE
nginx-59d795d786-5ln28 1/1 Running 0 34s
nginx-59d795d786-xnfjq 1/1 Running 0 34s
nginx-59d795d786-z86nn 1/1 Running 0 34s
[root@master ~]#kubectl get all
NAME READY STATUS RESTARTS AGE
pod/nginx-59d795d786-5ln28 1/1 Running 0 59s
pod/nginx-59d795d786-xnfjq 1/1 Running 0 59s
pod/nginx-59d795d786-z86nn 1/1 Running 0 59s
NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE
service/kubernetes ClusterIP 10.96.0.1 <none> 443/TCP 3d9h
NAME READY UP-TO-DATE AVAILABLE AGE
deployment.apps/nginx 3/3 3 3 59s
NAME DESIRED CURRENT READY AGE
replicaset.apps/nginx-59d795d786 3 3 3 59s
2. 发布容器（kubectl expose）
将资源暴露为新的 service
为 Deployment 的 nginx 创建 Service，并通过 Service 的 80 端口转发至容器的 80 端口上，Service 的名称为 nginx-service，类型为 NodePort。
[root@master ~]#kubectl expose deployment nginx --port=80 --target-port=80 --name=nginx-service --type=NodePort
service/nginx-service exposed
# 查看 Pod 网络状态详细信息和 Service 暴露的端口
[root@master ~]#kubectl get svc,pod -o wide
NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE SELECTOR
service/kubernetes ClusterIP 10.96.0.1 <none> 443/TCP 3d9h <none>
service/nginx-service NodePort 10.96.158.55 <none> 80:31083/TCP 3m37s run=nginx
NAME READY STATUS RESTARTS AGE IP NODE NOMINATED NODE READINESS GATES
pod/nginx-59d795d786-5ln28 1/1 Running 0 7m48s 10.244.1.3 node01 <none> <none>
pod/nginx-59d795d786-xnfjq 1/1 Running 0 7m48s 10.244.2.3 node02 <none> <none>
pod/nginx-59d795d786-z86nn 1/1 Running 0 7m48s 10.244.2.4 node02 <none> <none>
Kubernetes 之所以需要 Service，一方面是因为 Pod 的 IP 不是固定的（Pod 可能会重建），另一方面是因为一组 Pod 实例之间总会有负载均衡的需求。
Service 通过 Label Selector 实现的对一组 Pod 的访问。
对于容器应用而言，Kubernetes 提供了基于 VIP（虚拟 IP）的网桥的方式访问 Service，再由 Service 重定向到相应的 Pod。service 类型
- ClusterIP：提供一个集群内部的虚拟 IP 以供 Pod 访问（Service 默认类型）。
- NodePort：在每个 Node 上打开一个端口以供外部访问，Kubernetes 将会在每个 Node 上打开一个端口并且每个 Node 的端口都是一样的，通过
NodeIP:NodePort的方式。- LoadBalancer：通过外部的负载均衡器来访问，通常在云平台部署 LoadBalancer 还需要额外的费用。
查看关联的后端节点
[root@master ~]#kubectl get endpoints
NAME ENDPOINTS AGE
kubernetes 192.168.10.20:6443 3d10h
nginx-service 10.244.1.3:80,10.244.2.3:80,10.244.2.4:80 6m7s
查看 service 描述信息
[root@master ~]#kubectl describe svc nginx
Name: nginx-service
Namespace: default
Labels: run=nginx
Annotations: <none>
Selector: run=nginx
Type: NodePort
IP: 10.96.158.55
Port: <unset> 80/TCP
TargetPort: 80/TCP
NodePort: <unset> 31083/TCP
Endpoints: 10.244.1.3:80,10.244.2.3:80,10.244.2.4:80
Session Affinity: None
External Traffic Policy: Cluster
Events: <none>
查看负载均衡端口：1.18 版本之后，之前我们使用的是 userspace 和 iptables。
node01
[root@node01 ~]#yum -y install ipvsadm
......
[root@node01 ~]#ipvsadm -Ln
......
node02
[root@node02 ~]#yum -y install ipvsadm
......
[root@node02 ~]#ipvsadm -Ln
......
网页访问
查看访问日志
[root@master ~]#kubectl logs nginx-59d795d786-5ln28
10.244.1.1 - - [20/Jun/2022:05:05:59 +0000] "GET / HTTP/1.1" 200 612 "-" "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/102.0.5005.124 Safari/537.36 Edg/102.0.1245.44" "-"
2022/06/20 05:05:59 [error] 7#7: *1 open() "/usr/share/nginx/html/favicon.ico" failed (2: No such file or directory), client: 10.244.1.1, server: localhost, request: "GET /favicon.ico HTTP/1.1", host: "192.168.10.30:31083", referrer: "http://192.168.10.30:31083/"
10.244.1.1 - - [20/Jun/2022:05:05:59 +0000] "GET /favicon.ico HTTP/1.1" 404 571 "http://192.168.10.30:31083/" "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/102.0.5005.124 Safari/537.36 Edg/102.0.1245.44" "-"
[root@master ~]#kubectl logs nginx-59d795d786-xnfjq
[root@master ~]#kubectl logs nginx-59d795d786-z86nn
3. 更新容器（kubectl set）
查看当前运行的 nginx 版本号
[root@master ~]#curl -I http://192.168.10.40:31083/
HTTP/1.1 200 OK
Server: nginx/1.14.2
Date: Mon, 20 Jun 2022 05:22:03 GMT
Content-Type: text/html
Content-Length: 612
Last-Modified: Tue, 04 Dec 2018 14:44:49 GMT
Connection: keep-alive
ETag: "5c0692e1-264"
Accept-Ranges: bytes
将 nginx 版本更新为 1.15
[root@master ~]#kubectl set image deployment/nginx nginx=nginx:1.15
deployment.apps/nginx image updated
动态监听 pod 的创建过程：使用的是滚动更新方式，所以会先生成一个新的 pod，然后删除一个旧的 pod，往后以此类推。
[root@master ~]#kubectl get pods -w
NAME READY STATUS RESTARTS AGE
nginx-dc5dc5865-kgx5l 1/1 Running 0 57s
nginx-dc5dc5865-l245m 1/1 Running 0 79s
nginx-dc5dc5865-zpj48 1/1 Running 0 35s
......
更新规则可通过
kubetl describe deployment nginx的RollingUpdateStrategy查看，默认配置为25% max unavailable, 25% max surge，即按照 25% 的比例进行滚动更新。
查看 pod 的 ip 变化
[root@master ~]#kubectl get pods -o wide
NAME READY STATUS RESTARTS AGE IP NODE NOMINATED NODE READINESS GATES
nginx-dc5dc5865-kgx5l 1/1 Running 0 2m28s 10.244.2.5 node02 <none> <none>
nginx-dc5dc5865-l245m 1/1 Running 0 2m50s 10.244.1.4 node01 <none> <none>
nginx-dc5dc5865-zpj48 1/1 Running 0 2m6s 10.244.2.6 node02 <none> <none>
重新查看 nginx 版本号
[root@master ~]#curl -I 192.168.10.30:31083
HTTP/1.1 200 OK
Server: nginx/1.15.12
Date: Mon, 20 Jun 2022 05:27:26 GMT
Content-Type: text/html
Content-Length: 612
Last-Modified: Tue, 16 Apr 2019 13:08:19 GMT
Connection: keep-alive
ETag: "5cb5d3c3-264"
Accept-Ranges: bytes
4. 回滚容器（kubectl rollout）
查看历史版本
[root@master ~]#kubectl rollout history deployment/nginx
deployment.apps/nginx
REVISION CHANGE-CAUSE
1 <none>
2 <none>
执行回滚到上一个版本
[root@master ~]#kubectl rollout undo deployment/nginx
deployment.apps/nginx rolled back
[root@master ~]#curl -I 192.168.10.30:31083
HTTP/1.1 200 OK
Server: nginx/1.14.2
Date: Mon, 20 Jun 2022 05:30:36 GMT
Content-Type: text/html
Content-Length: 612
Last-Modified: Tue, 04 Dec 2018 14:44:49 GMT
Connection: keep-alive
ETag: "5c0692e1-264"
Accept-Ranges: bytes
回滚到指定版本
[root@master ~]#kubectl rollout history deployment/nginx
deployment.apps/nginx
REVISION CHANGE-CAUSE
2 <none>
3 <none>
[root@master ~]#kubectl rollout undo deployment/nginx --to-revision=2
deployment.apps/nginx rolled back
[root@master ~]#curl -I 192.168.10.30:31083
HTTP/1.1 200 OK
Server: nginx/1.15.12
Date: Mon, 20 Jun 2022 05:32:21 GMT
Content-Type: text/html
Content-Length: 612
Last-Modified: Tue, 16 Apr 2019 13:08:19 GMT
Connection: keep-alive
ETag: "5cb5d3c3-264"
Accept-Ranges: bytes
检查回滚状态
[root@master ~]#kubectl rollout status deployment/nginx
deployment "nginx" successfully rolled out
5. 删除容器（kubectl delete）
删除副本控制器
[root@master ~]#kubectl get deploy
NAME READY UP-TO-DATE AVAILABLE AGE
nginx 3/3 3 3 122m
[root@master ~]#kubectl delete deployment/nginx
deployment.apps "nginx" deleted
[root@master ~]#kubectl get deploy
No resources found in default namespace.
删除 service
[root@master ~]#kubectl get svc
NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE
kubernetes ClusterIP 10.96.0.1 <none> 443/TCP 3d13h
nginx-service NodePort 10.96.158.55 <none> 80:31083/TCP 122m
[root@master ~]#kubectl delete svc/nginx-service
service "nginx-service" deleted
[root@master ~]#kubectl get svc
NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE
kubernetes ClusterIP 10.96.0.1 <none> 443/TCP 3d13h
[root@master ~]#kubectl get all
NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE
service/kubernetes ClusterIP 10.96.0.1 <none> 443/TCP 3d13h
6. 定义版本（CHANGE-CAUSE）
在不定义 CHANGE-CAUSE 的情况下，缺省值为 none，当历史版本较多时，不便于咱们回滚时辨认版本号。因此，建议定义CHANGE-CAUSE为服务版本以帮助咱们辨认当前服务。
[root@master ~]# kubectl rollout history deploy/nginx-test
deployment.extensions/nginx-test
REVISION CHANGE-CAUSE
1 <none>
一般通过修改配置的方式定义 change-cause
[root@master ~]# kubectl edit deploy/nginx-test
......
kind: Deployment
metadata:
annotations:
#下行可定义历史版本revision
deployment.kubernetes.io/revision: "1"
#在Deployment的matadata项下的annotations中如下行定义change-cause
kubernetes.io/change-cause: "nginx1.14"
......
再次查看历史版本
[root@master ~]# kubectl rollout history deploy/nginx-test
deployment.extensions/nginx-test
REVISION CHANGE-CAUSE
1 nginx1.14
